Developing a Mathematical Model to Determine the Optimum Buffer Size and Redundancy Allocation in Series-Parallel Production Systems
Volume 9, Issue 2, Summer 2019, Pages 101-123
Mojtaba Aghaei, Maghsoud Amiri, Mohammad Taghi Taghavifard, Parham Azimi
Abstract The issue studied in this paper, considering redundancy allocation and buffer allocation problems simultaneously in a series-parallel production system. The purpose of this research is to improve the availability, total system costs and buffer capacity through determining the optimal buffers size between work stations, selecting high reliability machines and assigning them to work stations, and developing a proper maintenance and repair plan. In this paper, the preventive and emergency repairs to machines are allowed and their cost is considered in the cost function. Furthermore, it is assumed that machine failure rates are random and follows a distribution function such as Weibul. Given these assumptions, it is very difficult to obtain the availability and cost functions via mathematical relations, explicitly. Thus, a hybrid simulation, design of experiments, and neural network approach are applied to estimate the availability and cost functions. In order to analyze the proposed model, a numerical example was used
and based on the proposed methodology, was analyzed and evaluated. The model related to the problem was coded and solved by the NSGA-II algorithm and the Pareto set of answers was obtained. The results of the research indicated the validity of the proposed methodology for the problem under study.